[Orgmode] Re: How to do Properties search by define an agenda command

[Matt Lundin]

David Maus <address@hidden> writes:

> At Thu, 11 Nov 2010 20:51:58 -0500,
> Matt Lundin wrote:
>> > Looks like to use the intended functionality someone has to patch Org
>> > mode's tag search to handle multivalue properties.

AFAICT, the OP was not inquiring about a multivalue search, but rather
simply asking how to match an entire property value string (i.e., the
title of a book). The problems was caused not by unescaped spaces in
property values, but rather by how the custom agenda search was
constructed (e.g., incorrect property key, unescaped quote marks, etc.).

>> I don't believe the space in property values is meant to indicate
>> multiple values (i.e., in the same way that ":" separates tags). Here's
>> an example from the manual:
>
> This is a misunderstanding: Yes, you can use space characters in
> single value properties and use regexps to simulate multivalue
> properties.
>
> But you can't use Org's multivalue properties (C-h f
> org-entry-put-multivalued-property RET).

Good to know. I wasn't aware of multivalued properties. 

I think my comment still stands: currently, for normal tags/property
searches, single spaces are not intended to indicate multiple values.
The function org-tags-view invokes only the single value property
mechanism (i.e., org-cached-entry-get).

AFAICT, multivalued properties were introduced to accommodate org-attach
but they have not (yet) been used elsewhere in Org-mode. See the
following commit:

--8<---------------cut here---------------start------------->8---
commit d043e31182595983df3d191e80ca941ee171c400
Author: Carsten Dominik <address@hidden>
Date:   Wed Oct 1 09:25:18 2008 +0200

    Integrate John Wiegley's org-attach.el.
--8<---------------cut here---------------end--------------->8---

> Looks like an inconsistency or a glitch: Org supports putting multiple
> values in a property but has no reserved separator for multiple
> values.  So there is no way for a function recognize multivalue
> properties -- what makes it hard to perform a search for properties
> with multiple values w/o having the user enter a regular expression.

Currently, the only way to extract multivalue properties is to use the
API functions:

(info "(org) Using the property API")

I believe single value properties should be the default behavior for
searches (that is how the manual presents properties). I would certainly
*not* want to have to escape spaces in property drawers when, say,
entering AUTHOR and TITLE property values.

Currently, the search logic of is relatively straightforward:

 1. to force an exact property match, use TITLE="Quantum Mechanics"
 2. to allow partial matches, use a regexp: TITLE={Quantum}

Perhaps a patch could introduce an user option to use the multivalued
API in property searches. This could be a nice option for custom
commands. But I would recommend that the single value remain the
default.

Best,
Matt